It is expected that network access systems of various kinds, especially wireless network access systems (e.g. access nodes, such as base stations, of various types), will become increasingly ubiquitous. Accordingly, it is expected that mobile terminals (e.g. mobile phones and other mobile terminals) will be configured to be able to communicate with several different types of base stations, thereby providing flexibility to select the best type of base station to use for any given communication session. That is, it is expected that mobile terminals (a.k.a., user equipments (UEs)) will have multiple access interfaces. For example, in Long Term Evolution (LTE)/System Architecture Evolution (SAE) networks, also known as Evolved Packet System (EPS), multi-access is a key element. This means that an EPS UE will often face a situation where it has to select which out of multiple available network access systems to use (i.e. the UE has to perform access selection).
To leverage the benefits of having these multiple access interfaces it is desirable to have mechanisms and procedures in place to ensure that a mobile terminal uses its available access interfaces and network access systems as efficiently as possible. In this context, the perspectives of both the user of the mobile terminal and the operator of the network access system should preferably be considered. Accordingly, a new functional entity referred to as Access Network Discovery and Selection Function (ANDSF) has been introduced into the Third Generation Partnership Project (3GPP) network architecture, and corresponding functionality has been introduced in the UE (sometimes referred to as ueANDSF). The principle of ANDSF based access selection is that the ANDSF supplies rules/instructions to a UE, and the UE applies these rules/policies to its current contextual situation to arrive at an access selection result. That is, the ANDSF controls access selection indirectly and on a non-real-time scale. Hence, the current ANDSF access selection mechanism is not well suited to provide, for example, load balancing functionality.
What is desired are improved systems and methods for selecting a network access system. Henceforth the terms “access selection” and “cell selection” will be used as equivalents.